Conveyorized toaster ovens are known to the art. Toaster devices of the type which the present invention is generally applicable are described in U.S. Pat. No. 3,400,651 issued to Kenneth Gordon Hatch on Sept. 10, 1968 for "Automatic Toaster" and in U.S. Pat. No. 3,494,278, issued on Feb. 10, 1970 to the present inventor for "Automatic Toaster with Replaceable Food-Carrying Baskets." Both patents are assigned to the assignee of the present invention.
The toasters described in the aforementioned patents include a toaster housing and a plurality of radiant heating elements mounted within the housing. An endless conveyor is provided for moving food-carrying baskets adjacent the heating elements to toast food products held within the baskets. An opening is provided in the housing to allow the operator to place the food product in the baskets. The product is toasted as it passes through the housing and is dropped into a product receiving tray at the bottom of the housing.
Control of the toasting process is typically accomplished by varying the speed of the moving conveyor and/or by varying the temperature of or the number of heating elements employed for a particular product. In any event, with toasters of this type, the product must be removed quickly from the product tray because the product will become cold and will lose its warm and fresh taste. In some establishments the product is manually transferred to a separate warmer, because if the toasted product remains in the receiving tray it can become soggy due to impingement of infrared radiation on the top of the product. Such radiant heating has a tendency to drive moisture from the product, which in turn has a tendency to condense on the inside of the receiving tray.
The problem of moisture condensation in food warmers is known. For example, french fry warming devices are known which include a bin for receiving the french fries from a deep fat fryer. An infrared lamp is mounted above the bin with its rays directed onto the product. In early devices of this type, it was noticed that the french fries had a tendency to dry out due to the radiant heating driving moisture away from the product, with condensation occurring in the food bin. In newer french fry warmers, the problem has been overcome by embedding heating elements within the base of the product bin and providing controls to balance the radiant heating of the product and the heating of the bin.
By way of providing further background to the present invention, it should be mentioned that heating blankets consisting of a thin sheet containing embedded heating filaments are well known, and such pads have been employed in the food industry for warming food products. The blankets are applied to shelves, drawers, or other containers and usually include a rheostat device for controlling the amount of heat generated by the blanket. To the knowledge of the present inventor, such blankets have not heretofore been employed with conveyorized toasters of the type described in the above-mentioned Hatch and Chaudoir patents, nor have they been employed in conjunction with a radiant heating element to maintain toasted food products in a warm and fresh condition for an extended period.